scholarly journals CMOS-Compatible and Low-Cost Thin Film MACE Approach for Light-Emitting Si NWs Fabrication

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 966
Author(s):  
Antonio Alessio Leonardi ◽  
Maria José Lo Faro ◽  
Alessia Irrera
Keyword(s):  
Silicon Nanowires ◽  
Low Cost ◽  
Quantum Confinement Effect ◽  
High Surface ◽  
Volume Ratio ◽  
Cmos Technology ◽  
High Density ◽  
Synthesis Methods ◽  
Light Emitting ◽  
Strong Control

Silicon nanowires (Si NWs) are emerging as an innovative building block in several fields, such as microelectronics, energetics, photonics, and sensing. The interest in Si NWs is related to the high surface to volume ratio and the simpler coupling with the industrial flat architecture. In particular, Si NWs emerge as a very promising material to couple the light to silicon. However, with the standard synthesis methods, the realization of quantum-confined Si NWs is very complex and often requires expensive equipment. Metal-Assisted Chemical Etching (MACE) is gaining more and more attention as a novel approach able to guarantee high-quality Si NWs and high density with a cost-effective approach. Our group has recently modified the traditional MACE approach through the use of thin metal films, obtaining a strong control on the optical and structural properties of the Si NWs as a function of the etching process. This method is Complementary Metal-Oxide-Semiconductors (CMOS)-technology compatible, low-cost, and permits us to obtain a high density, and room temperature light-emitting Si NWs due to the quantum confinement effect. A strong control on the Si NWs characteristics may pave the way to a real industrial transfer of this fabrication methodology for both microelectronics and optoelectronics applications.

Effect of current density on the porous silicon preparation as gas sensors**

2021 ◽  
Vol 30 (1) ◽  
pp. 257-264
Author(s):  
Muna H. Kareem ◽  
Adi M. Abdul Hussein ◽  
Haitham Talib Hussein
Keyword(s):  
Porous Silicon ◽  
Gas Sensors ◽  
Current Density ◽  
Room Temperature ◽  
Low Cost ◽  
High Surface ◽  
Volume Ratio ◽  
Etching Time ◽  
Force Microscopy ◽  
Materials Used

Abstract In this study, porous silicon (PSi) was used to manufacture gas sensors for acetone and ethanol. Samples of PSi were successfully prepared by photoelectrochemical etching and applied as an acetone and ethanol gas sensor at room temperature at various current densities J= 12, 24 and 30 mA/cm2 with an etching time of 10 min and hydrofluoric acid concentration of 40%. Well-ordered n-type PSi (100) was carefully studied for its chemical composition, surface structure and bond configuration of the surface via X-ray diffraction, atomic force microscopy, Fourier transform infrared spectroscopy and photoluminescence tests. Results showed that the best sensitivity of PSi was to acetone gas than to ethanol under the same conditions at an etching current density of 30 mA/cm2, reaching about 2.413 at a concentration of 500 parts per million. The PSi layers served as low-cost and high-quality acetone gas sensors. Thus, PSi can be used to replace expensive materials used in gas sensors that function at low temperatures, including room temperature. The material has an exceptionally high surface-to-volume ratio (increasing surface area) and demonstrates ease of fabrication and compatibility with manufacturing processes of silicon microelectronics.

scholarly journals A Review of Carbon Nanotubes-Based Gas Sensors

2009 ◽  
Vol 2009 ◽  
pp. 1-24 ◽  
Author(s):  
Yun Wang ◽  
John T. W. Yeow
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Low Cost ◽  
High Surface ◽  
Hollow Structure ◽  
Volume Ratio ◽  
Fast Response ◽  
Sensing Technology ◽  
Structure Of Nanomaterials

Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nanotubes (CNTs) has fuelled the inventions of gas sensors that exploit CNTs' unique geometry, morphology, and material properties. Upon exposure to certain gases, the changes in CNTs' properties can be detected by various methods. Therefore, CNTs-based gas sensors and their mechanisms have been widely studied recently. In this paper, a broad but yet in-depth survey of current CNTs-based gas sensing technology is presented. Both experimental works and theoretical simulations are reviewed. The design, fabrication, and the sensing mechanisms of the CNTs-based gas sensors are discussed. The challenges and perspectives of the research are also addressed in this review.

Structural and Optical Studies of CdS Nanocomposites Synthesized by Various Routes

2008 ◽  
Vol 8 (8) ◽  
pp. 4188-4192 ◽  
Author(s):  
Gouri Sankar Paul ◽  
Pratima Agarwal
Keyword(s):  
Quantum Confinement Effect ◽  
High Surface ◽  
Aqueous Media ◽  
Thermo Gravimetric Analysis ◽  
Volume Ratio ◽  
Stoichiometric Ratio ◽  
Particle Sizes ◽  
Gravimetric Analysis ◽  
Phonon Modes ◽  
Cds Nanocomposites

Structural and optical properties of CdS nanocomposites prepared by two different routes are presented in this paper. While CdS prepared by aqueous media results in the formation of nanoparticles of particle sizes 8–9 nm; the solvothermal process results in the formation of nanorods of diameter 40–50 nm and length 450–750 nm where particle sizes were confirmed by SEM and TEM. XRD studies confirm that the structure of these nanocomposites is wurzite. EDAX give the stoichiometric ratio. UV-Vis and photoluminescence (PL) measurements show a blue shift compared to bulk CdS, supporting quantum confinement effect. Nanocomposites are found to be stable up to 650 °C was observed by thermo gravimetric analysis (TGA). The Raman scattering studies show that in addition to LO and TO phonon modes, peak corresponding to surface phonon modes are present in both cases, which are due to high surface to volume ratio. The CdS nanocomposites can therefore be used for various stable optoelectronic devices.

scholarly journals Mesoporous Nanocast Electrocatalysts for Oxygen Reduction and Oxygen Evolution Reactions

Inorganics ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 98 ◽  
Author(s):  
Tatiana Priamushko ◽  
Rémy Guillet-Nicolas ◽  
Freddy Kleitz
Keyword(s):  
Oxygen Reduction ◽  
High Activity ◽  
Oxygen Evolution ◽  
Noble Metal ◽  
Noble Metals ◽  
Low Cost ◽  
High Surface ◽  
Clean Energy ◽  
Production Costs ◽  
Synthesis Methods

Catalyzed oxygen evolution and oxygen reduction reactions (OER and ORR, respectively) are of particular significance in many energy conversion and storage processes. During the last decade, they emerged as potential routes to sustain the ever-growing needs of the future clean energy market. Unfortunately, the state-of-the-art OER and ORR electrocatalysts, which are based on noble metals, are noticeably limited by a generally high activity towards one type of reaction only, high costs and relatively low abundance. Therefore, the development of (bi)functional low-cost non-noble metal or metal-free electrocatalysts is expected to increase the practical energy density and drastically reduce the production costs. Owing to their pore properties and high surface areas, mesoporous materials show high activity towards electrochemical reactions. Among all synthesis methods available for the synthesis of non-noble mesoporous metal oxides, the hard-templating (or nanocasting) approach is one of the most attractive in terms of achieving variable morphology and porosity of the materials. In this review, we thus focus on the recent advances in the design, synthesis, characterization and efficiency of non-noble metal OER and ORR electrocatalysts obtained via the nanocasting route. Critical aspects of these materials and perspectives for future developments are also discussed.

scholarly journals III–V Nanowires: Synthesis, Property Manipulations, and Device Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Ming Fang ◽  
Ning Han ◽  
Fengyun Wang ◽  
Zai-xing Yang ◽  
SenPo Yip ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Cost Effective ◽  
Research Field ◽  
Synthesis Methods ◽  
Comprehensive Overview ◽  
Device Applications ◽  
Property Control

III–V semiconductor nanowire (NW) materials possess a combination of fascinating properties, including their tunable direct bandgap, high carrier mobility, excellent mechanical flexibility, and extraordinarily large surface-to-volume ratio, making them superior candidates for next generation electronics, photonics, and sensors, even possibly on flexible substrates. Understanding the synthesis, property manipulation, and device integration of these III–V NW materials is therefore crucial for their practical implementations. In this review, we present a comprehensive overview of the recent development in III–V NWs with the focus on their cost-effective synthesis, corresponding property control, and the relevant low-operating-power device applications. We will first introduce the synthesis methods and growth mechanisms of III–V NWs, emphasizing the low-cost solid-source chemical vapor deposition (SSCVD) technique, and then discuss the physical properties of III–V NWs with special attention on their dependences on several typical factors including the choice of catalysts, NW diameters, surface roughness, and surface decorations. After that, we present several different examples in the area of high-performance photovoltaics and low-power electronic circuit prototypes to further demonstrate the potential applications of these NW materials. Towards the end, we also make some remarks on the progress made and challenges remaining in the III–V NW research field.

Effect of Ethylenediamine Tetraacetic Acid in Electrochemical Deposition of Zinc Selenide

2012 ◽  
Vol 501 ◽  
pp. 231-235
Author(s):  
Sook Mey Ng ◽  
Zulkarnain Zainal ◽  
Mat Yunus Wan Mahmood
Keyword(s):  
Zinc Selenide ◽  
Surface Defects ◽  
Low Cost ◽  
Quantum Confinement Effect ◽  
Green Light ◽  
Photoluminescence Intensity ◽  
Tetraacetic Acid ◽  
Photoelectrochemical Performance ◽  
Light Emitting ◽  
Ethylenediamine Tetraacetic Acid

Zinc selenide based materials are suitable for fabrication of light emitting diodes operating in the blue-green light. In fabrication of zinc selenide films, electrodeposition method appears to be the simplest and low-cost technique. In this work, the application of ethylenediamine tetraacetic acid (EDTA) in electrodeposition of zinc selenide was investigated to evaluate its effect on the optical and electronic properties of the films. It was found that the presence of EDTA stabilized the cathodic over potential during deposition. The zinc selenide deposits consist of small grain size deposits which contribute to enhance the photoelectrochemical performance. Besides that, the zinc selenide films produced in the presence of EDTA also shows high photoluminescence intensity due to minimized surface defects on the glass substrate. The film shows photoluminescence peak at the blue region of wavelength due to its quantum confinement effect. The optical property of zinc selenide film was measured using ultraviolet-visible spectrophotometer. The band gap of zinc selenide is 2.65 eV with direct transition.

scholarly journals Exploration of Microbial Factories for Synthesis of Nanoparticles – A Sustainable Approach for Bioremediation of Environmental Contaminants

2021 ◽  
Vol 12 ◽  
Author(s):  
Riti T. Kapoor ◽  
Marcia R. Salvadori ◽  
Mohd Rafatullah ◽  
Masoom R. Siddiqui ◽  
Moonis A. Khan ◽  
...  
Keyword(s):  
Low Cost ◽  
High Surface ◽  
Pollution Abatement ◽  
Chemical Properties ◽  
Volume Ratio ◽  
Production Method ◽  
Research Field ◽  
Renewable Materials ◽  
Synthesis Of Nanoparticles ◽  
Nanoparticles Synthesis

The nanomaterials synthesis is an intensifying research field due to their wide applications. The high surface-to-volume ratio of nanoparticles and quick interaction capacity with different particles make them as an attractive tool in different areas. Conventional physical and chemical procedures for development of metal nanoparticles become outmoded due to extensive production method, energy expenditure and generation of toxic by-products which causes significant risks to the human health and environment. Hence, there is a growing requirement to search substitute, non-expensive, reliable, biocompatible and environmental friendly methods for development of nanoparticles. The nanoparticles synthesis by microorganisms has gained significant interest due to their potential to synthesize nanoparticles in various sizes, shape and composition with different physico-chemical properties. Microbes can be widely applied for nanoparticles production due to easy handling and processing, requirement of low-cost medium such as agro-wastes, simple scaling up, economic viability with the ability of adsorbing and reducing metal ions into nanoparticles through metabolic processes. Biogenic synthesis of nanoparticles offers clean, non-toxic, environmentally benign and sustainable approach in which renewable materials can be used for metal reduction and nanoparticle stabilization. Nanomaterials synthesized through microbes can be used as a pollution abatement tool as they also contain multiple functional groups that can easily target pollutants for efficient bioremediation and promotes environmental cleanup. The objective of the present review is to highlight the significance of micro-organisms like bacteria, actinomycetes, filamentous fungi, yeast, algae and viruses for nanoparticles synthesis and advantages of microbial approaches for elimination of heavy metals, dyes and wastewater treatment.

scholarly journals ZnFe2O4, a Green and High-Capacity Anode Material for Lithium-Ion Batteries: A Review

2021 ◽  
Vol 11 (24) ◽  
pp. 11713
Author(s):  
Marcella Bini ◽  
Marco Ambrosetti ◽  
Daniele Spada
Keyword(s):  
Lithium Ion Batteries ◽  
Broad Class ◽  
High Surface ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
Rate Capability ◽  
Volume Ratio ◽  
Lithium Ion ◽  
Structural Features ◽  
Synthesis Methods

Ferrites, a broad class of ceramic oxides, possess intriguing physico-chemical properties, mainly due to their unique structural features, that, during these last 50–60 years, made them the materials of choice for many different applications. They are, indeed, applied as inductors, high-frequency materials, for electric field suppression, as catalysts and sensors, in nanomedicine for magneto-fluid hyperthermia and magnetic resonance imaging, and, more recently, in electrochemistry. In particular, ZnFe2O4 and its solid solutions are drawing scientists’ attention for the application as anode materials for lithium-ion batteries (LIBs). The main reasons are found in the low cost, abundance, and environmental friendliness of both Zn and Fe precursors, high surface-to-volume ratio, relatively short path for Li-ion diffusion, low working voltage of about 1.5 V for lithium extraction, and the high theoretical specific capacity (1072 mA h g−1). However, some drawbacks are represented by fast capacity fading and poor rate capability, resulting from a low electronic conductivity, severe agglomeration, and large volume change during lithiation/delithiation processes. In this review, the main synthesis methods of spinels will be briefly discussed before presenting the most recent and promising electrochemical results on ZnFe2O4 obtained with peculiar morphologies/architectures or as composites, which represent the focus of this review.

scholarly journals Research Progress on the Applications of Electrospun Nanofibers in Catalysis

Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 9
Author(s):  
M. Olga Guerrero-Pérez
Keyword(s):  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Electrospun Nanofibers ◽  
Internal Diffusion ◽  
Research Progress ◽  
Bibliographic Analysis ◽  
Low Resistance ◽  
Electro Catalysis

During the last two decades, electrospinning has become a very popular technique for the fabrication of nanofibers due to its low cost and simple handling. Nanofiber materials have found utilization in many areas such as medicine, sensors, batteries, etc. In catalysis, these materials also present important advantages, since they present a low resistance to internal diffusion and a high surface area to volume ratio. These advantages are mainly due to the diameter–length proportion. A bibliographic analysis on the applications of electrospun nanofibers in catalysis shows that there are two important groups of catalysts that are being investigated, based on TiO2 and in carbon materials. The main applications found are in photo- and in electro-catalysis. The present study contributes by reviewing these catalytic applications of electrospun nanofibers and demonstrating that they are promising materials as catalysts, underlining some works to prove the advantages and possibilities that these materials have as catalysts. On one hand, the possibilities of synthesis are almost infinite, since with coaxial electrospinning quite complex nanofibers with different layers can be prepared. On the other hand, the diameter and other properties can be controlled by monitoring the applied voltage and other parameters during the synthesis, being quite reproducible procedures. The main advantages of these materials can be grouped in two: one related to their morphology, as has been commented, relative to their low resistance and internal diffusion, that is, their fluidynamic behavior in the reactor; the second group involves advantages related to the fact that the active phases can be nanoscaled and dispersed, improving the activity and selectivity in comparison with conventional catalytic materials with the same chemical composition.

scholarly journals Starch-Based Hybrid Nanomaterials for Environmental Remediation

2021 ◽  
Author(s):  
Ashoka Gamage ◽  
Thiviya Punniamoorthy ◽  
Terrence Madhujith
Keyword(s):  
Metal Oxide ◽  
Environmental Remediation ◽  
Membrane Filtration ◽  
Anthropogenic Activities ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Hybrid Nanomaterials ◽  
Metal Metal

Environmental pollution is becoming a major global issue with increasing anthropogenic activities that release massive toxic pollutants into the land, air, and water. Nanomaterials have gained the most popularity in the last decades over conventional methods because of their high surface area to volume ratio and higher reactivity. Nanomaterials including metal, metal oxide, zero-valent ions, carbonaceous nanomaterials, and polymers function as adsorbents, catalysts, photocatalysts, membrane (filtration), disinfectants, and sensors in the detection and removal of various pollutants such as heavy metals, organic pollutants, dyes, industrial effluents, and pathogenic microbial. Polymer-inorganic hybrid materials or nanocomposites are highly studied for the removal of various contaminants. Starch, a heteropolysaccharide, is a natural biopolymer generally incorporated with other metal, metal oxide, and other polymeric nanoparticles and has been reported in various environmental remediation applications as a low-cost alternative for petroleum-based polymers. Therefore, this chapter mainly highlights the various nanomaterials used in environmental remediation, starch-based hybrid nanomaterials, and their application and limitations.

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